It was the claim that caught our eye: a cordless screwdriver that charges in 90 seconds. It's either the first capacitor-powered cordless tool we've ever seen, or just one of those physics-defying accomplishments that exist only in the rarified pocket dimensions of late-night infomercials. And the YouTube commercial for Coleman's new 5.4V Cordless FlashCell Screwdriver doesn't help—it's silly to the point of camp, an unintentional self-parody of zany product spots that themselves may only exist in Saturday Night Live skits. But there it was, the miraculous claim: a minute and a half per charge, over and over and over again.

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We've tested this cordless screwdriver, and in this case, the truth is stranger than any hype. The $90 FlashCell doesn't use a new kind of lithium-ion cell, or a trusty nickel-cadmium battery, or even ancient lead-acid technology. This bizarre device doesn't use any batteries at all—it's powered by a capacitor. So like massive, lab-based lasers and the tiny flash in your camera, it charges up quickly, and discharges pretty quickly, too.

According to Team Products International, the company behind the FlashCell, it runs for about half as long as an equivalent tool, such as Skil's lithium-ion-powered 3.6V iXO cordless screwdriver. Specifically, that means around 22 screws per charge, compared to 37 for the iXO. The company also estimates that the capacitor can handle over 500,000 full-charge cycles. And since there's no memory effect, you don't even have to wait the full 90 seconds before getting back to work. You can snap it into place (a satisfying, spring-loaded operation, by the way—reminiscent of old Fisher-Price toys), then watch the gloriously analog needle in the power gauge swing upward for, say, 45 seconds.

In our tests, the 90-second number held up, and although it ran out of juice relatively quickly, as an around-the-house screwdriver, the Flashcell has a lot going for it. Similar low-powered drivers last longer per charge, and lose power less quickly when not in use, but they can also take hours to recharge. Team Products claims that the Flashcell should retain about 85 percent of its charge when sitting on a shelf for three months. But, again, we're talking 90 seconds.

So this isn't a breakthrough, but it is an incredibly innovative way to build a specific kind of cordless tool. It would, however, take a breakthrough to make capacitors more than a niche power source. Jeff Plane, business manager for power and hand tools at Team Products, points out that having to constantly recharge a cordless drill, for example, would be a deal-breaker—a half-finished hole is much worse than a half-driven screw. For now, Plane says the only capacitor-powered tool the company is developing is a smaller, pistol-grip screwdriver, along the lines of Skil's iXo. High-voltage capacitors, after all, have been known to overheat and explode. And that, you could argue, is what lithium-ion is for. —Erik Sofge